blood trans

Question 1

what class are antibodies

Answer 1

IgM class,

Question 2

what temp are they active at

Answer 2

reactive at 37ºC

Question 3

why must the correct blood type br transfered

Answer 3

capable of fully activating complement, so are able to cause potentially fatal haemolysis (destruction of red cells) if incompatible blood is transfused.

Question 4

what are the blood types

Answer 4

a
b
ab
o

Question 5

what are the antigens on each

Answer 5

a- a antigen
b- b antigen
ab - both
o - no antigen, H stem only

Question 6

having a type blood what antibodies would be present in the plasma

Answer 6

anti b

Question 7

and if you had b type

Answer 7

anti a

Question 8

if you had ab

Answer 8

no antibodies

Question 9

if o

Answer 9

anti a and anti b

Question 10

how are ab antigens on red blood cells formed

Answer 10

dding one or other sugar residue onto a common glycoprotein and fucose stem (H antigen) on the red cell membrane.

Question 11

how are antigen determined

Answer 11

by corresponding genes:

Question 12

what does the a gene code for

Answer 12

The A gene codes for an enzyme that adds N-acetyl galactosamine to the common H antigen

Question 13

and b gene codes for

Answer 13

2. The B gene codes for enzyme which adds galactose

Question 14

both ab antigens are said to b e

Answer 14

A and B genes are co-dominant

Question 15

what is the o gene said to be

Answer 15

O gene is recessive

If a person is blood group A - genes could be AA or OA

Question 16

in a lab what can you see if teh wrong blood is given

Answer 16

agglutination, clumped

Question 17

what is the Rh system based on

Answer 17

antigen D

Question 18

what r the blood groups

Answer 18

Blood groups: RhD positive (if have D antigen) or RhD negative (if not).

Question 19

explain what the genes cause

Answer 19

D gene codes for D antigen on red cell membrane.
d gene codes for no antigen and is recessive (no actual antigen).
Therefore:

Group RhD negative = dd
Group RhD positive = DD or Dd

Question 20

what do p People who lack the RhD antigen (ie: RhD negative) create

Answer 20

CAN make anti-D antibodies AFTER they are exposed to the RhD antigen - either by transfusion of RhD positive blood, or in women if they are pregnant with an RhD positive foetus

Question 21

what class are anti D antibodies

Answer 21

Anti-D antibodies are IgG class antibodies.

Question 22

Implications of anti-D antibodies:

Answer 22

Future transfusions– the patient must in future, have RhD negative blood (otherwise their anti-D would react with RhD positive blood - causes delayed haemolytic transfusion reaction– with anaemia; high bilirubin (from breakdown of red cells); jaundice etc.).

HDN

Question 23

what is HDN

Answer 23

haemolytic disease of the newborn- if RhD neg mother has anti-D, then in the next pregnancy, if fetus is RhD positive: mother’s IgG anti-D antibodies can cross the placenta (only IgG class antibodies can do this) – attach to the RhD positive red cells of the foetus and cause haemolysis of foetal red cells - if severe: hydrops fetalis and death. If less severe, the baby survives but after birth, the high bilirubin levels can cause brain damage or death.

Question 24

if it is less severe will the baby die

Answer 24

no survives after birth , but high bilirubin levels cab cause brain damage an death

Question 25

you must

Answer 25

Transfuse blood of same RhD group (no harm to give RhD negative to a positive patient - just wasteful!

Question 26

what blood can you give to anyone

Answer 26

Group O negative blood (i.e. Rh D negative)

Question 27

are there any other antigens

Answer 27

yes, behshamar
Once patients have formed an antibody, we must use corresponding antigen negative blood; or else there is a risk of a delayed haemolytic reaction.

Question 28

how to check abo and rhd compatibility

Answer 28

antibody screen

Question 29

function of antibody screen

Answer 29

exclude any clinically significant immune antibodies:

Question 30

how it works

Answer 30

Patient plasma is incubated with 2 or 3 different fully typed ‘screening’ red cells, which are known to possess all the blood group antigens which matter clinically.

Question 31

if negative

Answer 31

any donor blood which is ABO & RhD compatible can be given.

Question 32

if positive

Answer 32

the antibody must be identified with the use of a large panel of red cells. Donor units of blood that lack the corresponding blood group antigen are then chosen for cross matching with the recipient’s plasma prior to transfusion.

Question 33

sumarise compatabillity

Answer 33

​1. Patient blood sample (plasma + cells).

ABO group (test patient’s red cells with known anti-A and anti-B reagents).
RhD group (test patient’s red cells with known anti-D and reagent).
Select donor blood of the same ABO & RhD group. 
Antibody screen +/- antibody panel, to identify antibody/ies. 

2​. Cross-match: patient’s serum mixed with chosen donor red cells - should not react: if reacts (agglutinates) = incompatible.

Question 34

what tests di blood donor go thru

Answer 34

1. Group & screening:

2. Infection testing:

Question 35

what is Prion Disease

Answer 35

Prion proteins have been found in membranes of lymphocytes and platelets and the prions of variant Creutzfeldt-Jacob disease (CJD) are found in lymphoreticular tissues
A blood test to exclude any donor with vCJD is not yet available

Question 36

is the whole blood given

Answer 36

no, just the part they require
e.g. only platelets and factor 8
risk of at risk of fluid overload, for patient a red cell transfusion for anaemia